hugo/tpl/transform/remarshal.go

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package transform
import (
"bytes"
"errors"
"strings"
"github.com/gohugoio/hugo/parser"
"github.com/spf13/cast"
)
// Remarshal is used in the Hugo documentation to convert configuration
// examples from YAML to JSON, TOML (and possibly the other way around).
// The is primarily a helper for the Hugo docs site.
// It is not a general purpose YAML to TOML converter etc., and may
// change without notice if it serves a purpose in the docs.
// Format is one of json, yaml or toml.
func (ns *Namespace) Remarshal(format string, data interface{}) (string, error) {
from, err := cast.ToStringE(data)
if err != nil {
return "", err
}
from = strings.TrimSpace(from)
format = strings.TrimSpace(strings.ToLower(format))
if from == "" {
return "", nil
}
mark, err := toFormatMark(format)
if err != nil {
return "", err
}
fromFormat, err := detectFormat(from)
if err != nil {
return "", err
}
var metaHandler func(d []byte) (map[string]interface{}, error)
switch fromFormat {
case "yaml":
metaHandler = parser.HandleYAMLMetaData
case "toml":
metaHandler = parser.HandleTOMLMetaData
case "json":
metaHandler = parser.HandleJSONMetaData
}
meta, err := metaHandler([]byte(from))
if err != nil {
return "", err
}
var result bytes.Buffer
if err := parser.InterfaceToConfig(meta, mark, &result); err != nil {
return "", err
}
return result.String(), nil
}
func toFormatMark(format string) (rune, error) {
// TODO(bep) the parser package needs a cleaning.
switch format {
case "yaml":
return rune(parser.YAMLLead[0]), nil
case "toml":
return rune(parser.TOMLLead[0]), nil
case "json":
return rune(parser.JSONLead[0]), nil
}
return 0, errors.New("failed to detect target data serialization format")
}
func detectFormat(data string) (string, error) {
jsonIdx := strings.Index(data, "{")
yamlIdx := strings.Index(data, ":")
tomlIdx := strings.Index(data, "=")
if jsonIdx != -1 && (yamlIdx == -1 || jsonIdx < yamlIdx) && (tomlIdx == -1 || jsonIdx < tomlIdx) {
return "json", nil
}
if yamlIdx != -1 && (tomlIdx == -1 || yamlIdx < tomlIdx) {
return "yaml", nil
}
if tomlIdx != -1 {
return "toml", nil
}
return "", errors.New("failed to detect data serialization format")
}